For example, as disclosed in JP 2009-71044 A, a semiconductor device having a convex portion provided on a surface of a semiconductor layer has been conventionally known. The semiconductor device described in paragraph [0016], FIG. 1, etc. of the above publication includes a semiconductor layer, an emitter electrode formed on the surface of the semiconductor layer, a first convex portion provided along the outer periphery of the surface of the semiconductor device so as to make a round inside the periphery, and a second convex portion formed in an inner range of the first convex portion.
Patent Literature 1: JP 2009-71044 A